We have developed a noncontact temperature sensor using a silver halides infrared optical fiber. An infrared radiation from a heat source is transferred by a silver halides infrared optical fiber and measured by infrared sensors such as a thermopile and a thermal optical power-meter. The relationships between the temperature of a heat source and the output voltage of the thermopile and the optical power of a thermal optical power-meter are determined. The measurable temperature range using a thermopile and a thermal optical power-meter are from 100 to $750^{circ}C$ and from 30 to $750^{circ}C$ respectively. It is expected that a noncontact temperature sensor using infrared optical fiber can be developed for medical and industrial usages based on the results of this study.